This application proposes experiments to study mechanisms by which the ciliary epithelium and aqueous outflow channels maintain intraocular pressure. Physiologic and pharmacologic influences, especially of the adrenergic nervous system, on aqueous humor formation and aqueous outflow, will be studied. Outflow resistance will be determined by constant pressure perfusion. Determination of aqueous humor formation will be made using inulin clearance in some experiments and turnover studies of aqueous humor chemistries in others. Enzymatic determinations for adenyl cyclase, Na-K ATPase and membrane bound enzymes will be done in preparations of ciliary epithelium in parallel with these physiologic studies. Studies of the uptake, binding, and degradation and localization of norepinephrine and its analogs involve labelling techniques, liquid scintillation counting and column chromatography. Assays for enzymes degrading catecholamines will require labelled substrates.